Case in point: Ben Affleck hid inside the Batmobile and surprised dozens of unsuspecting fans. The actor had ulterior motives for being there, though. "I've teamed up with Omaze to invite you to join the cast at the premiere of Batman v Superman: Dawn of Justice. Then you'll hang with me before you take a ride in the Batmobile," he said. "To give you just a small preview of what that's like, I'm here at Warner Bros. Studios Tour Hollywood to borrow it for a little while."

As each tourist group was ushered in, Affleck popped the top of his car.

"Are you real?" one fan asked.

"I am real!" Affleck said as the crowd laughed and snapped pictures.

Affleck put one girl in the driver's seat with him. "Whoa! How do you drive this thing?" she asked. He couldn't resist throwing a little shade at his rival superhero. "Superman doesn't even have a cool car to put you in," Affleck said. "I've got like eight of these cars." When another fan confessed he was rooting for Henry Cavill's character, Affleck joked, "Superman has a Subaru!"

Jokes aside, Affleck had serious reasons for wanting to partner with Omaze. For a $10 entry fee, one entrant and a friend will win a spin in the Batmobile, plus a helicopter ride with Cavill, a photo with Affleck at the premiere and a chance to photobomb the cast with Jesse Eisenberg. Proceeds from the entry fee will benefit Affleck's Eastern Congo Initiative, as well as The SEED Project (nominated by Eisenberg) and the Durrell Wildlife Conservation Trust (nominated by Cavill).